Ensure confirm() returns a boolean after Enter

src/prompt_toolkit/application/application.py

@@ -1055,8 +1055,6 @@ def _breakpointhook(self, *a: object, **kw: object) -> None:
         import pdb
         from types import FrameType
 
-        TraceDispatch = Callable[[FrameType, str, Any], Any]
-
         @contextmanager
         def hide_app_from_eventloop_thread() -> Generator[None, None, None]:
             """Stop application if `__breakpointhook__` is called from within
@@ -1110,9 +1108,7 @@ async def in_loop() -> None:
                 done.set()
 
         class CustomPdb(pdb.Pdb):
-            def trace_dispatch(
-                self, frame: FrameType, event: str, arg: Any
-            ) -> TraceDispatch:
+            def trace_dispatch(self, frame: FrameType, event: str, arg: Any) -> Any:
                 if app._loop_thread is None:
                     return super().trace_dispatch(frame, event, arg)
 

src/prompt_toolkit/shortcuts/prompt.py

@@ -1527,6 +1527,11 @@ def no(event: E) -> None:
         session.default_buffer.text = "n"
         event.app.exit(result=False)
 
+    @bindings.add("enter")
+    def _(event: E) -> None:
+        "Disallow submitting without an answer."
+        pass
+
     @bindings.add(Keys.Any)
     def _(event: E) -> None:
         "Disallow inserting other text."

tests/test_shortcuts.py

@@ -1,7 +1,15 @@
 from __future__ import annotations
 
-from prompt_toolkit.shortcuts import print_container
-from prompt_toolkit.shortcuts.prompt import _split_multiline_prompt
+from functools import partial
+from importlib import import_module
+from unittest.mock import patch
+
+import pytest
+
+from prompt_toolkit.input import create_pipe_input
+from prompt_toolkit.output import DummyOutput
+from prompt_toolkit.shortcuts import confirm, print_container
+from prompt_toolkit.shortcuts.prompt import PromptSession, _split_multiline_prompt
 from prompt_toolkit.widgets import Frame, TextArea
 
 
@@ -66,3 +74,19 @@ def test_print_container(tmpdir):
         text = fd.read()
         assert "Hello world" in text
         assert "Title" in text
+
+
+@pytest.mark.parametrize(
+    ("answer", "expected"),
+    [("y", True), ("Y", True), ("n", False), ("N", False)],
+)
+def test_confirm_ignores_enter_without_answer(answer, expected):
+    with create_pipe_input() as input:
+        input.send_text(f"\r{answer}")
+        session = partial(PromptSession, input=input, output=DummyOutput())
+        prompt_module = import_module("prompt_toolkit.shortcuts.prompt")
+
+        with patch.object(prompt_module, "PromptSession", session):
+            result = confirm()
+
+    assert result is expected